1. Technical Field
The field of art to which this invention pertains may be generally located in the class of devices relating to fan guards. Class 416, Fluid Reaction Surfaces, Sub-Class 247R, U.S. Pat. Office Classifications, appears to be the applicable general area of art to which the subject matter similar to this invention has been classified in the past.
2. Background Information
Air circulation fans are widely used in industrial environments, such as automobile plants, and other type factories. It is time consuming and expensive to assemble such industrial fans in industrial plants, and especially where such fans may be located many feet above the floor level. Industrial fans must be cleaned at least once a year because the edges of the fan blades get loaded with dirt, and if the blades are not cleaned periodically the fan motor will overheat. Such cleaning operations involve a disassembly of the fan guard to permit the maintenance workers to clean the fan blades, and such an operation is time consuming. Furthermore, when an industrial fan motor becomes inoperative or is damaged in some manner whereby the motor or the fan must be replaced, the disassembly of the fan guard from the motor is time consuming and comprises a costly operation. Heretofore, the fan guards for many industrial fans have comprised a front guard member and a back or rear guard member, with said guard members being held together by hooks. Experience has shown that when the prior art hooks are used for holding a fan front guard member on a fan rear guard member, the fan front guard member can be accidentally knocked off of the fan rear guard member, as for example, if the fan front guard member is hit by a fork lift carrying articles through a plant.
Heretofore, in order to overcome the accidental disassembly of a fan front guard from a fan rear guard it has been proposed to use tie wraps to tie the two fan guards together in addition to the hooks. However, a disadvantage in using tie wraps in conjunction with hooks is that the use of tie wraps adds additional disassembly time, and assembly time, when it is necessary to provide maintenance work on a fan, and they are not strong enough to provide positive security. Another disadvantage of the aforementioned type industrial fan guards is that they require more then one maintenance worker to assemble and disassemble the fan rear guard on a motor, as well as assembling and disassembling the fan front guard to the fan rear guard and secure them together. The use of the prior art hooks to secure a fan front guard to a fan rear guard requires at least two men, with one man holding the fan guards together while another maintenance worker employs a tool, such as a screw driver, to mount the hooks in place on the guard members to secure them together.